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	<div id="winchm_template_button"><A href="_hstring2.htm" title="Previous topic"><img id="winchm_template_prev" alt="Previous topic" src="../template2/btn_prev_n.gif" border="0"></a><A href="_imggp.htm" title="Next topic"><img id="winchm_template_next" alt="Next topic" src="../template2/btn_next_n.gif" border="0"></a></div>
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<A href="introduction6.htm">Debugging Tools for Windows (WinDbg, KD, CDB, NTSD)</A> &gt; <A href="debugger_reference.htm">Debugger Reference</A> &gt; <A href="debugger_commands.htm">Debugger Commands</A> &gt; <A href="general_extensions.htm">General Extension Commands</A> &gt; </div>
	<div id="winchm_template_title">!htrace</div>
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	<div id="winchm_template_content"><div id="mainSection"><p>The <b>!htrace</b> extension displays stack trace information for one or more handles.</p>
<p>User-Mode Syntax</p>
<pre class="syntax"><b>!htrace </b>[<i>Handle </i>[<i>Max_Traces</i>]] 
<b>!htrace -enable </b>[<i>Max_Traces</i>]
<b>!htrace -snapshot</b>
<b>!htrace -diff</b>
<b>!htrace -disable</b>
<b>!htrace -?</b> </pre>
<p>Kernel-Mode Syntax</p>
<pre class="syntax">
    <b>!htrace </b>[<i>Handle</i> [<i>Process </i>[<i>Max_Traces</i>]]] 
<b>!htrace -?</b> 
</pre>
<h2><a id="ddk__htrace_dbg"></a><a id="DDK__HTRACE_DBG"></a>Parameters</h2>
<p></p>
<dl>
<dt><a id="_______Handle______"></a><a id="_______handle______"></a><a id="_______HANDLE______"></a>       <i>Handle</i>      </dt>
<dd>
<p>Specifies the handle whose stack trace will be displayed. If <i>Handle</i> is 0 or omitted, stack traces for all handles in the process will be displayed.</p>
</dd>
<dt><a id="_______Process______"></a><a id="_______process______"></a><a id="_______PROCESS______"></a>       <i>Process</i>      </dt>
<dd>
<p>
       (Kernel mode only)  Specifies the process whose handles will be displayed.  If <i>Process</i> is 0 or omitted, then the current process is used.  In user mode, the current process is always used.  </p>
</dd>
<dt><a id="_______Max_Traces______"></a><a id="_______max_traces______"></a><a id="_______MAX_TRACES______"></a>       <i>Max_Traces</i>      </dt>
<dd>
<p>Specifies the maximum number of stack traces to display.  In user mode, if this parameter is omitted, then all the stack traces for the target process will be displayed.  </p>
</dd>
<dt><a id="_______-enable______"></a><a id="_______-ENABLE______"></a>       <b>-enable</b>      </dt>
<dd>
<p>(User mode only)  Enables handle tracing and takes the first snapshot of the handle information to use as the initial state by the <b>-diff</b> option.</p>
</dd>
<dt><a id="_______-snapshot______"></a><a id="_______-SNAPSHOT______"></a>       <b>-snapshot</b>      </dt>
<dd>
<p>(User mode only)  Takes a snapshot of the current handle information to use as the initial state by the <b>-diff</b> option.</p>
</dd>
<dt><a id="_______-diff______"></a><a id="_______-DIFF______"></a>       <b>-diff</b>      </dt>
<dd>
<p>(User mode only)  Compares current handle information with the last snapshot of handle information that was taken.  Displays all handles that are still open.</p>
</dd>
<dt><a id="_______-disable______"></a><a id="_______-DISABLE______"></a>       <b>-disable</b>      </dt>
<dd>
<p>(User mode only; Windows Server 2003 and later only)  Disables handle tracing.  In Windows XP, handle tracing can be disabled only by terminating the target process.</p>
</dd>
<dt><a id="_______-_______"></a>       <b>-?</b>      </dt>
<dd>
<p>Displays some brief Help text for this extension in the Debugger Command window.</p>
</dd>
</dl>
<h3><a id="DLL"></a><a id="dll"></a>DLL</h3>
<table>
<tr>
<td>
<p><b>
          Windows 2000
         </b></p>
</td>
<td>
<p>Unavailable </p>
</td>
</tr>
<tr>
<td>
<p><b>
          Windows XP and later
         </b></p>
</td>
<td>
<p>
<dl>
<dt>
          Kdexts.dll
          </dt>
<dt>Ntsdexts.dll
         </dt>
</dl>
</p>
</td>
</tr>
</table>
<p> </p>
<h3><a id="Additional_Information"></a><a id="additional_information"></a><a id="ADDITIONAL_INFORMATION"></a>Additional Information</h3>
<p>For information about handles, see the Microsoft Windows SDK documentation and <i>Microsoft Windows Internals</i> by Mark Russinovich and David Solomon. (These resources may not be available in some languages 

and countries.)
To display further information about a specific handle, use the <a href="#Bookmark2252"><b>!handle</b></a> extension.</p>
<h2>Remarks</h2>
<p>Before <b>!htrace</b> can be used, handle tracing must be enabled. One way to enable handle tracing is to enter the <b>!htrace -enable</b> command. When handle tracing is enabled, stack trace information is saved each time the process opens a handle, closes a handle, or references an invalid handle.  It is this stack trace information that <b>!htrace</b> displays.</p>
<div class="alert"><b>Note</b>    You can also enable handle tracing by activating Application Verifier for the target process and selecting the <b>Handles</b> option.</div>
<div> </div>
<p>Some of the traces reported by <b>!htrace</b> may be from a different process context.  In this case, the return addresses may not resolve properly in the current process context, or may resolve to the wrong symbols.</p>
<p>The following example displays information about all handles in process 0x81400300:</p>
<pre class="syntax" xml:space="preserve"><code>kd&gt; !htrace 0 81400300
Process 0x81400300
ObjectTable 0xE10CCF60

--------------------------------------
Handle 0x7CC - CLOSE:
0x8018FCB9: ntoskrnl!ExDestroyHandle+0x103
0x801E1D12: ntoskrnl!ObpCloseHandleTableEntry+0xE4
0x801E1DD9: ntoskrnl!ObpCloseHandle+0x85
0x801E1EDD: ntoskrnl!NtClose+0x19
0x010012C1: badhandle!mainCRTStartup+0xE3
0x77DE0B2F: KERNEL32!BaseProcessStart+0x3D
--------------------------------------
Handle 0x7CC - OPEN:
0x8018F44A: ntoskrnl!ExCreateHandle+0x94
0x801E3390: ntoskrnl!ObpCreateUnnamedHandle+0x10C
0x801E7317: ntoskrnl!ObInsertObject+0xC3
0x77DE23B2: KERNEL32!CreateSemaphoreA+0x66
0x010011C5: badhandle!main+0x45
0x010012C1: badhandle!mainCRTStartup+0xE3
0x77DE0B2F: KERNEL32!BaseProcessStart+0x3D
--------------------------------------
Handle 0x7DC - BAD REFERENCE:
0x8018F709: ntoskrnl!ExMapHandleToPointerEx+0xEA
0x801E10F2: ntoskrnl!ObReferenceObjectByHandle+0x12C
0x801902BE: ntoskrnl!NtSetEvent+0x6C
0x80154965: ntoskrnl!_KiSystemService+0xC4
0x010012C1: badhandle!mainCRTStartup+0xE3
0x77DE0B2F: KERNEL32!BaseProcessStart+0x3D
--------------------------------------
Handle 0x7DC - CLOSE:
0x8018FCB9: ntoskrnl!ExDestroyHandle+0x103
0x801E1D12: ntoskrnl!ObpCloseHandleTableEntry+0xE4
0x801E1DD9: ntoskrnl!ObpCloseHandle+0x85
0x801E1EDD: ntoskrnl!NtClose+0x19
0x010012C1: badhandle!mainCRTStartup+0xE3
0x77DE0B2F: KERNEL32!BaseProcessStart+0x3D
--------------------------------------
Handle 0x7DC - OPEN:
0x8018F44A: ntoskrnl!ExCreateHandle+0x94
0x801E3390: ntoskrnl!ObpCreateUnnamedHandle+0x10C
0x801E7317: ntoskrnl!ObInsertObject+0xC3
0x77DE265C: KERNEL32!CreateEventA+0x66
0x010011A0: badhandle!main+0x20
0x010012C1: badhandle!mainCRTStartup+0xE3
0x77DE0B2F: KERNEL32!BaseProcessStart+0x3D

--------------------------------------
Parsed 0x6 stack traces.
Dumped 0x5 stack traces.</code></pre></div></div>	
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